1. Technical Field
This invention relates generally to pistons, and more particularly to methods of forming pin holes in the pistons and boring systems therefor.
2. Related Art
Pistons have diametrically opposite pin holes configured for receipt of a wrist pin. The wrist pin is couple to a connecting rod to provide a transfer rotation motion of a crankshaft to reciprocal linear motion of the piston with a cylinder bore. The wrist pin can be configured for relative movement within the pin holes and/or with a bore of the connecting rod, as desired. Regardless, it is desirable to minimize frictional wear between the wrist pin and the pin holes and/or connecting rod bore. Accordingly, precise formation of the respective bores is critical to provide the assembly with a long and useful life.
Commonly, the pin bores of the piston are formed by holding the piston in a fixed position while moving a cutting tool linearly through pin bosses of the piston. Typically, the pin holes are formed in separate operations at separate times, or they are formed at the same time through the use of separate cutting tools arranged on opposite sides of the piston. The cutting tool is configured to rotate and to move linearly along an axis transverse to a central longitudinal axis of the piston.